The present invention relates to an electromagnet device.
C Japanese Utility Model Publication No. 1983-157947 discloses one of the conventional electromagnetic device to be used in an electromagnetic relay. The electromagnetic relay disclosed in the said document attracts and retains a movable iron piece and uses residual magnetism of a magnetic circuit, wherein the magnetic circuit consists of an iron core with a coil wound around, an iron core frame made of a semi-hard magnetic material, and the movable iron piece. In this electromagnetic relay, since the iron core frame is made of a semi-hard magnetic material, the iron core frame itself is magnetized to become a magnet.
However, in this electromagnetic relay, it is difficult to obtain a desirable attraction force between the iron core and the movable iron piece. Hence, for example, when a large switching load is needed, it is difficult to drive a movable touch piece having a large spring force. Particularly while maintaining a moved state, a strong retention force is needed. Accordingly, it is difficult to put this electromagnetic relay into practical use.